feature: Proposing Private AI integration for PII detection

Did you check the docs?

[x] I have read all the NeMo-Guardrails docs

Is your feature request related to a problem? Please describe.

Add support for Private AI to safeguard Personally Identifiable Information and address one of the big safety concern for using LLMs.

Describe the solution you'd like

To start with it'd be nice to have a Private AI PII detection action, something like detect_pii which can be used in input, output or retrival retrieval.

Example usage

rails:
  input:
    flows:
      - detect pii on input
  output:
    flows:
      - detect pii on output
  retrieval:
    flows:
      - detect pii on retrieval

The implementation can be similar to what we already have for sensitive_data_detection action.

The implementation can be later extended to include:

PII masking
Synthetic entity generation

Describe alternatives you've considered

We currently have an action sensitive_data_detection that uses Microsoft Presidio. By introducing Private AI, we will expand support for more entities, improve detection accuracy, and provide additional features, including support for multiple file formats.

The support can also be extended to features like masking, synthetic entity genertion, and different file types.

Additional context

Additional resources

Private AI developer docs: https://docs.private-ai.com/introduction/
Supported entities: https://docs.private-ai.com/entities/
Supported file types: https://docs.private-ai.com/files/

NVIDIA / NeMo-Guardrails